Pen



FIG. 1 is a front perspective view of a pen showing my new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a front side elevational view thereof; and,

FIG. 8 is a rear side elevational view thereof.

The broken lines in the drawings are shown for the purpose of illustrating environmental matter and form no part of the claimed design. 

The ornamental design for a pen, as shown and described. 